Shaping the meeting edges of curved blanks in the manufacture of sheet metal pipes and the like



July 28, 1931. w, HUME 1,816,534,

SHAPING THE MEETING EDGES OF CURVED BLANKS IN THE MANUFACTURE SHEET METAL PIPES AND THE LIKE Filed June 6. 1928 4 Sheets-Sheet 1 July 28, 193 w. R. HUME 4 SHAPING THE MEETING EDGES OF CURVED BLANKS IN THE MANUFACTURE OF SHEET METAL PIPES AND THE LIKE Filed June 6, 1928 4 Sheets-Sheet 2 July 28, 1931. w. R. HUME 1,816,534

SHAPING THE MEETING EDGES OF CURVED BLANKS IN THE MANUFACTURE OF SHEET METAL PIPES AND THE LIKE Filed June 6, 1928 4 Sheets-Sheet 3 Wei/er fie z naaja /7 -x ma July 28, 1931. w. R. HUME 1,816,534

SHAPING THE' MEETING EDGES OF CURVED BLANKS IN THE MANUFACTURE OF SHEET METAL PIPES AND THE LIKE Filed June 6. 1928 4 Sheets-Sheet 4 i/izmi/ I Patented July 28, 1931 UNITED STATES PATENT GFFICE SHAPIN G THE MEETING EDGES OF CURVED BLANKS IN THE MANUFACTURE OF SHEET METAL FIRES AND THE LIKE Application filed June 6, 1928, Serial No.

This invention relates to the manufacture of pipes and like hollow or tubular articles from metal sheets or plates which are first rolled or shaped in a bending machine or the like so as to form curved blanks the meeting edges of which are subsequently secured to gether. For instance, by welding, to thereby form the pipe or like article.

A dificulty hitherto experienced in the manufacture of sheet metal pipes and the like as above mentioned is that the meeting edge portions of the curved blanks after leaving the bending machine are somewhat flat thus forming a corresponding flat or distorted portion adjacent the seam or joint in the finished article.

The object of the present invention is to provide an improved method and means of treating the meeting edge portions of the curved blanks so that the resultant portion of the finished article is of proper arcuate formation.

The method in accordance with the invention consists primarily in bending the meeting edge portions of the sheet metal blank slightly inwards prior to the welding or uniting of said edges, the result being that the natural spring or resilience of the metal causes said inbent edges to assume, in the finished article, the correct arc of the adjacent portion of the metal tube.

Secondly, the method involves the bending of the meeting edges as above mentioned, progressively from end to end of the curved blanks.

The invention also contemplates bringing the meeting edges of the curved blank, after they have sprung from the inbent attitude into the required curvature, into closely abutted relationship and tack welding or similarly securing them together at longitudinal intervals prior to the final welding operation.

Anv suitable apparatus may be employed in carrying out the above mentioned method but a preferred form of apparatus for the purpose will now be described.

Referring to the drawings which form part of this specification Figure l is an end view of a pipe blank after it has been curved in a bending machine 283,356, and in Australia June 27, 1827.

and showing the meeting edge portions of the blank slightly flattened.

Figure 2 is an end view of the curved blank after its meeting edge portions have been bent slightly inwards in accordance with this invention.

Figure 3 is an end view in which the meeting edge portions have assumed the required curvature and have been closely abutted so that they may be welded together to form a pipe of perfect cross-sectional shape.

Figure 4 is a sectional elevation of (Io-operating die members by which the meeting edges of a curved pipe blank may be bent inwardly, preparatory to welding operations.

Figure 5 is a cross sectional view of the cooperating die members.

Figure 6 is an end view of the co-operating die members and shows means for supporting the lower die member within a curved blank.

Figure 7 is a part sectional side elevation of a machine for carrying out the invention. Various parts are broken away or omitted for convenience of illustration.

Figure 8 is a plan view of the machine,

Figure 9 is an end view of the machine.

Figure 10 is an enlarged view taken approximately on the line XX in Figure 9.

Figure 11 is a cross sectional View illustrating means for bringing the longitudinal edges of a blank against each other prep-aratory to uniting same.

Figure 12 is a view similar to Figure 11 but in which the longitudinal edges are shown in abutted relationship.

Figure 13 is a contracted side elevation of apparatus for closing the meeting edges of a curved blank and embodies the means shown in Figures 11 and 12.

Figure 14 is a plan of Figure 13.

In Figure 1 a curved pipe blank is shown with its meeting edged portion 2a, 2b, slightly flattened due to the normal operation of the roller bending machine by which the blank has been curved. Figure 2 depicts the edge portions 2a, 215, in unbroken lines b nt inwardly in accordance as shown in broken lines with this invention, from which position said edge portion, owing to the resilience thereof, spring outwards into the desired curvature as shown in broken lines. In Figure 3 the edge portions 2a, 2b, are shown closely abutted so that they may be welded together by an electrode 3 and will thus assure the correct are or curvature in the finished article. The numeral 4 indicates a backing memberor bearer which may engage the under side of the work immediately beneath the electrodes. Prior to the actual welding together of the meeting edge portions 2a., 2b, the meeting edges of the blank 2 may be closely abutted and tackwelded as will be more ful y described hereinafter.

Apparatus for carrying out the invention includes a suitable base from which upstands a framework which may comprise metal plates 6 secured to and upstanding from the base and standards 7 for bracing the plates. A shaft 9 is supported in bearings 8 (Figure 10) to extend transversely of the framework and is fitted with fast and loose pulleys 11 12 having sui able belt shifting gear 13 associated therewith as seen in Figu and 9.

Mounted on the shaft 9 where it extends across an opening in the framework is an eccentric 16 around which is fitted a verticallea ting ram or presser head 17. prefhaving a detachable can 18 to facilhe ram 17 may carry adj acent its lower end guide blocks 19 adapted to slide in vertical guides 21 formed in or attached o the main framework.

An upper or outer die block 22 may be attached by bolts 23 to the lower end of the ram 17. As seen more clearly in Figures 5 and 6 the underneath face 24 of the die block 22 is of concave formation and is provided with a central d pending ridge or projection 26 of approximately v shape in cross-section, the sides of the projection being curved to the point of the V.

Disposed beneath the outer die is a lower or inner die block 28 the upper face 29 of which is of convex formation and is provided with a central groove or recess 31 which in cross-sectional shape, corresponds substantially to the ridge or project on 2'5 of the outer die, the recess 31 being situated immediately beneath said projection as shown more clearly in Figure 5.

The inner die 28 is preferably carried by a vertically adjustable frame comprising a pair of relatively thin vertical legs 32 capable of passing freely between the me he edge portions 2a, 2b. of the blank 2. the i j u spanned at their lower ends by angle 33 which are disposed within he blank being treated as indicated in Fi (3 and 9. The inner (he may be attached to the e angle pieces by belts or screws The legs 32 may be braced immediately above tie blank 2 by suitable brac members or stilleners 86 secured to the i n framework.

At their upper ends the legs 32 may be secured to a pair of arms 37 which are spaced apart centrally of their length to accommodate a bearing 38 for a rod 39. The screwed lower end portion 41 of the rod operates within a vertically screwed socket member 42 suitably secured to the upper part of the main framework above the cross shaft 9. By turning a handwheel 43 at the upper end of the rod 39 the entire frame carrying the inner die 28 may be adjusted vertically to bring the latter into the desired position. The frame may be locked in position by passing a pin 44 through the hand-wheel 43 and into an adjacent part of the main framework.

On the base 6 is a track comprising a pair of rails 46 which may consist of the upstandin flanges of a channel section girder 47 laid upon the base. Running upon this track are the wheels 48 of a work supporting carriage 49, the direction of travel of which is lengthwise of the die blocks 22, 28.

The carriage is provided adjacent its ends with work holders each of which may comprise a pair of crossed arms 51, pivoted at their lower ends to the carriage, and adapted to receive between them the curved blank 2 as indicated in Figure 9. The arms 51 may be adjusted to accommodate work of different sizes and held in the desired adjusted positions by a bolt 52 or the like passed through slots 58 in the arms of'the crossing point of the latter.

In operation the curved blank 2 is placed upon the work holders 51 with the meeting edges 2a, 2b, of the blank disposed immediately above the lower die block 28 and at 0pposite sides of the groove or recess 31 thereof the legs 82 supporting the inner die passing through the gap between the meeting edges of the blanks. The vertically recipro eating ram or presser head 17 is then brought into operation so that the outer die 22 is forced downwardly against the meeting edge portions of the blank with the result that said edges are pressed downwardly between the ridge 26 of the upper die block and thus turned slightly downwards and inwards as indicated. hen the meeting edge portions of the blank are relieved of pressure they spring outwardly and assume the required curvature as before mentioned. The pressing operation is carried out progressively from end to end of the blank, the work carriage 49 being intermittently advanced between the successive may comprise a cam 56 mounted on the cross shaft 9, and contacting with a roller 57 carried at the free end of a lever pivoted at its .other end to a bracket 59 on the main framework. A connecting rod 61 may extend between this lever 58 and a second lever 62 pivoted to a bracket 63 on the framework. From the free end of a third lever 64, also pivoted to the bracket 63, a rod, chain or fleizt ble line 65 may extend to a weighted arm 66 mounted to swing about a spindle 67 which may extend transversely beneath the main framework. This arm may carry a pawl 68 adapted to engage the teeth of ratchet wheel 69 fixed on the spindle which may also be fitted with a toothed pinion 71 meshing with a toothed rack 72 attached to and extending longitudinally beneath the work carriage 49.

As the outer die 22 is raised from work the foregoing mechanism automatically advances the carriage so as to bring another portion of the work into position for the next pressin" operation, the legs 32 of the inner die supporting frame preventing circumferential or sideward disalignment of the meeting edge portions of the blank relative to the dies 22, 28, during advances of the carriage 49.

Provision may be made for varying the amount of travel of the work carriage for each action of the cam operated feeding mechani'sm. For instance the lower end of the flexible line 65 may be attached at various positions along the weighted arm 66.

After the meeting edge portions of the blank have been so treated for the whole of their lengths, the blank is removed and the meeting edges, which at this stage are spaced apart, are closely abutted and tack welded or suitably held together, at longitudinally spaced intervals preparatory to the welding together of the meeting edges along the entire lengths thereof. In order to close the blank or bring the meeting edges 20, 203., there of into closely abutted relationship, the meeting edge portions 2a, 2b, are adapted to bear against a stop face or abutment 7-3 (as indicated in Figures 11 to M) whilst pressure, acting towards said step face, is applied simultaneously to the external surface of the blank at two zones or points 74, 74a, (Fig ures 11 and 12) which. in endwise viewing of the blank, are preferably spaced equi-distant from the gap between said meeting edges, 20, 2d, and from each other. By thus applying pressure to the the meeting edge portions 261,26, are caused to slide inwardly so that the meeting edges 20, 2d, are brought and held against each other as in Figure 12, without in any way distorting the curvature of the blank which is thus of perfect circular form, in cross section. lVhilst the meeting edges are held together as aforesaid they are tack welded at suitably spaced intervals, or

b ink otherwise temporarily secured together, so that th cylindrical blank may be removed for final welding along the line of the joint.

The stop face or abutment may be constituted by a horizontal flange ?5, of a stop member 76 adapted to extend longitudinally above the blank being treated and to be held stationary during operations. This stop member may have secured thereto at its ends nuts 77 through which extend screws 78 fitted at their upper ends with hand wheels 79 whereby the screws may be operated to raise or lower the nuts and the stop member according to the diameter of the blank to be operated upon. The nuts 77 may be prevented from rotating by bein fitted closely within pairs of upstanding plates 81 suitably supported at each end of a framework 82.

The means for applying pressure to the blank includes a presser member 83 of substantially channel shape in cross section which is arranged with its side flanges 8d projecting upwards so that the curved blank, with its meeting edge portions 26:, 26, uppermost, may rest upon the upper edges of said ges The presser,which preferably extends longitudinally for the entire length of the blank, may be forced upwardly by a plurality of rams 86 operating in vertical cylinders Si" from the open upper ends of which the rams are projected by fluid pressure. The rams bear at their upper ends against the under surface of the horizontal flange or base 88 of the channel shaped presser 83, and preferably mid-way of the width ther f. Theram cylinders 87 may be suitably ached to the framework 82 at appropr rte longitud 'ly spaced intervals, and fluid under pressure may be led to the cylinders by a main service pipe 89 and a number of branch service pipes-91 (Figure 13) a suitable valre 92 may be provided whereby the fluid may be discharged from said cylinders by way of an exnaus; pipe 93.

The presser 83 may have one or more guide members 94 secured to 1 id depending therefrom and adapted to sude within opposite plates of the main framework 82. Presser members 83 of different widths may be employed according to the diameter of the blank to be treated, so that in all cases the blank will be subjected to exter al pressure at three points or zones spaces. approximately equidistantly around the circumference thereof, the pressure applied at two of said points acting in a counter direction to the pressure at the third point zone which is disposed adjacent the meeting edge portions of the blank.

To ensure that the end edges of the blank are perfectly true, that is to say, that they are perfectly square, with or at right angles to the length of the blank, one end edge of the. blank may bear against a stop member 95 (Figures 13 and l-l) whilst a wedge 96 may pressure, and subsequently pre be driven between the other end edge and an inclined face of another stop member 97 as indicated in Figure ll, said stop members being disposed in alignment with the meeting edge portions 2a, 2b, of the blank.

After the presser 83 has been raised to an extent suflicient to cause the meeting edges 20, 2a, to be abutted, and whilst the presser remains in such raised attitude the meeting edges are tack welded. To permit access to be had to said meeting edges so that tack welding operations may be carried out, the horizontal tiar Tet and, if desired, the adjacent portion of the stop member 76 may have gaps or recesses 98 formed therein at suitably spaced intervals. Subsequently the edges may be welded continuously along their length.

Having now described my intention what- I claim as new and desire to secure by Letters Patent is l 1. A method of treating the m portions of curved sheet n-eta bodies, consisting in press edge portions of a curved r wards prior to uniting said er. i that they may spring outwa the tesired curvature upon of such clease ssin said edge portions against a stop face abuinzent whereby they are held in coinciding arcuite formation with the meeti ed" against each other pre story to being welded along the line of said edges.

A method of treating the meeting edge iortions of curved sheet metal blanks in the ianufacture of pipes and like hollow bodies, onsisting in oressing' or bending 'd edge ortious of a curved l lan slightly inwards rior to uniting said edge p rtions so that may spring;- outwardly to assume the deireu curvature upon release 01 ch pressure,

ubsequently pressing saidvor 'e portions S again. t a stop face or abutment whereby they a'e held in coinciding arcuate formatioi vih the meeting abutting against each preparatory to being wel led along the edges, and temporarily unitin z of of the blank wh lst they are tl 1 abutted relationship. ii, imp oved method of manufacturing iollow bodies from sheet con 'sts in rlliug t lair fori pressure tne er go 1" will sprin; oiuiwardly nd assume the ature with a gap betweei their I e es, sub, quentlv subjecting the blank to external pressiu'e a three points or zones ce thereof, the pressure applied in counter (llspace'd approximately equidistant around the i c unfer id points actir rection to the pressure at the third point which is disposed adjacent the longitudinal meeting edges of the blank so that said edges are forced into and held in aoutted relationship, tacking or spot weldi said shutter edges together at longitudin subsequently welding said tinuously along their len Apparatus for treating me al blanks in the mam an; other hollow bodies, cratingupper or outer and (fllrittl fracture of com prising c'i-ol l war or inner die members, said outer die member having a concave vorking face provided with tral longitudinally rid of the blank are bent slightly in wards.

A pparatus for treating curved sheet metal blanks in the manufacture of pipes and other hollow bodies, comprising co-operating upper r outer and lower or inner die members, said outer die member having a concave working face provided with a conral longitudinally extending ridge or projection approximating in shape to an obtuse angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a substantially tubular blank, said inner die member having a convex working face provided with a groove or recess which conforms approximately in disposition and contour to said ridge adapted to contact with the inner surfaces of said meeting edge portions, and means for forcing said outer die member against the o iter surfaces of said meeting edge portions, said inner die member being stationarily mounted so as to pass witnin the blank.

6, Apparatus for treating curved sheet metal blanks in the mam'lfaeture of pipes and other hollow bodies, comprising CO-f perat-ing upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge or projection approximating in shape to an obtuse angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge portioi of curved blank, said inner die member having a convex workingface provided with a groove or recess which couforim; approximately in disposition and contour to said ridge adapted to contact with the lilner surfaces of said meeting edge portions,

means for reciprocating said outer die member towards and from the inner die member, and a support for the blank adapted to be advanced longitudinally at intervals when said outer die member is out of contact with the blank.

7. Apparatus for treating curved sheet metal blanks in the manufacture of pipes and other hollow bodies, comprising co-opcrating upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge or projection approximately in shape to an obtuse angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a blank, said inner die member having a convex working face provided with groove or recess which conforms approximately in disposition and contour to said ridge and is adapted to contact with the inner surfaces of said meetin edge portions, means for forcing said die members towards one another, whereby the longitudinal edge portions of the blank are bent slightly inwards, and means for automatically and iniermittently advancing the blank between successive pressing operations of said dies.

8. Apparatus for treating curved sheetmetal blanks in the manufacture of pipes and other hollow bodies, comprising co-operating upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge or projection approximating in shape to an obtuse angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge po tions of a curved blank, said inner die member having a convex working face provided with a groove or recess which conforn s approximately in disposition and contour to said ridge adapted to contact with the inner surfaces of said meeting edge portions, means for reciprocating said outer die member towards and from the inner die member, and a wheeled carriage adapted to support the blank under treatment, said carriage being operatively connected with the means for reciprocating the outer die whereby said carriage is automatically and intermittently advanced longitudinally with the blank between successive pressing actions of the dies.

9. Apparatus for treating curved sheet metal blanks in the manufacture of pipes and other hollow bodies, comprising co-operating upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge or projection approximating in shape to an obtuse angled V adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a blank, said inner die member having a convex working face provided with a groove or recess which conforms approximately in disposition and contour to said ridge adapted to contact with the inner surfaces of said meeting edge portions, means for reciprocating said outer die member towards and from the inner die member, a wheeled carriage adapted to support the blank under treatment, said carriage being operatively con nected with the means for reciprocating the outer die whereby said carriage is automatically intermittently advanced longitudinally with the blank between successive pressing actions of the dies, a toothed rack on said carriage, a pinion engaging said rack and means operable by the outer die reciproeating means to turn said pinion at periods when the outer die is free of the blank.

10. Apparatus for treating curved sheet metal blanks in the manufacture of pipes and other hollow bodies, comprising co-operating upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge or projection approximating in shape to an obtuse angled V adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a blan said inner die member having a convex working face provided with a groove or recess which. conforms approximately in disiosition and contour to said ridge adapted to contact with the inner surfaces of said meeting edge portions, means for reciprocating said outer die member towards and from the inner die member, a wheeled carriage adapted to support the blank under treatment, said carriage being operatively connected with the means for reciprocating the outer die whereby said carriage is automatically and intermittently advanced longitudinally with the blank between successive pressing actions of the dies, a toothed rack on said carriage, a pinion engaging said rack, and pawl and ratchet mechanism operatively connected with the outer die reciprocating means and adapted to turn said pinion in one direction only at periods when the outer die is free of the blank.

11 Apparatus for creating curved sheet metal blanks in the manufacture of pipes and other hollow bodies. comprising co-operating upper or outer and lower or inner die members,said outer die members having a concave working face provided with a central longitudinally extending ridge or projection approximating in shape to obtuse angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a curved blank, said inner die member having a convex working face provided with a groove or recess which conforms approximately in disposition and contour to said ridge and is adapted to contact with the inner surfaces of said meeting edge portions,

means for forcing said die members towards one another whereby the longitudinal edge portions of the blank are bent slightly in wards, and at least one relatively thin leg to support said inner die member which is adapted to pass through a gap between the meeting edges of the blank.

12. Apparatus for treating curved sheet metal blanks in the manufacture of pipes and other hollow bodies, comprising co-operating upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge of projection approximating in shape to an 01311186 angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a blank, said inner die member having a convex working face provided with a groove or recess which conforms approximately in disposition and contour to said ridge and is adapted to contact with the inner surfaces of said meeting edge portions, means for forcing said die members towards one another whereby the longitudinal edge portions of the blank are bent slightly inwards, and means for adjusting said inner die member in relation to said outer die member.

13. Apparatus for treating curved sheet metal blanks in the manufacture of pipes and other hollow bodies, comprising oo-operating upper or outer and lower or inner die members, said outer die member having a concave working face provided with a central longitudinally extending ridge or projection approximating in shape to an obtuse angled V, adapted to contact with the outer surfaces of the longitudinal meeting edge portions of a substantially tubular blank, said inner die member having a convex working face pro vided with a groove or recess which conforms approximately in disposition and contour to said ridge and is adapted to contact with the inner surfaces of said meeting edge portions of the blank, means for forcing said die members towards one another whereby said edge portions of the blank are bent slightly inwards, an adjustable frame, at least one relatively thin leg to support said inner die member, which forms a part of the adjustable frame and is adapted to pass through the gap between the meeting edges of the blank, a main framework carrying a screw threaded socket member, and an adjustin screw connected to said adjustable frame and operating in said socket member.

In testimony whereof I aiiix my signature.

YVALTEP REGINALD HUME. 

